OUTLINE: If possible, patients produce a 3-day pooled sputum sample prior to bronchoscopy. Patients then undergo tracheobronchial white-light bronchoscopy followed by autofluorescence bronchoscopy using the Lung Imaging Fluorescence Endoscopic (LIFE) Device attached to a computerized video camera. Visualized tissue is classified as either normal, abnormal, or suspicious. Abnormal or suspicious tissue is biopsied, as is tissue from 1 or 2 randomly chosen normal sites. Immunohistochemical analysis of the biopsy material is conducted without knowledge of the bronchoscopic results. Patients unable to produce a sputum sample prior to bronchoscopy are required to do so after bronchoscopy.